Kristaps Porzingis suffered a non-contact leg injury in the Celtics’ playoff game against the Heat on Monday night.
The team dubbed him doubtful to return with right calf tightness.
Porzingis was dribbling the ball out by the 3-point line, being guarded by Heat big man Bam Adebayo, when he came up limp.
The Celtics’ star headed to the locker room late in the second quarter, looking visibly agitated and putting his jersey over his face.
“He looks like he’s got major concern right now,” TNT play-by-play broadcaster Brian Anderson said.
“He does,” agreed color commentator Stan Van Gundy.
Porzingis accounted for seven of the Celtics’ 53 first-half points, adding three rebounds before his exit.
The Celtics hold a 2-1 lead in the best-of-seven series against the Heat, and entered Monday’s game as the overwhelming favorites to win the Eastern Conference, and the betting favorites overall to win the NBA championship.
Porzingis averaged 20.1 points and 7.2 rebounds per game in the regular season this year.